condensation issue

[mwe3302]

Hello all, my name is mike, i am new to the site. Here is my issue. I think it was due to the extreme heat change in march this year, so the other day i was bored and thought i would admire my new garage, so i go inside and happen to look up. I noticed all the insulation was or looked like there was mold growing all over the paper on the insulation, the paper was very wet. By the way i have R-19 kraft faced insulation on the ceiling, 16" on center.
So i kind of panicked the garage and slab were build last june, so i grabed a step ladder and felt it. It was moisture, i went upstairs and felt the insulation, it was dry. I felt all the way down through it, it also was dry. So it was just to paper side,or the kraft side.

I imediatly opened the doors to help dry it out. Then i called a couple lumber places and asked them about my delema. 3 places said my slab is still curing ,and one asked if the concrete guys put styrofoam under it, i said no. And they said maybe i have clay under my gravel, they said that could cause water to come through the slab and hit the first surface it comes to, what do you all think? I do not heat this yet either., oh i forgot to mention i use a 2011 yamaha grizzly700 eps/fi SE to plow my door yard and i park it in the garage on a big blue tarp. Well there was a good size puddle of water under the atv from the snow melting. Could this of caused the condensation on the insulation on the ceiling? I have been leaving my windows in the garage opened a crack since this happened the other day. Anyway let me know what you guys/girls think please, thanks in advance..... Mike

 

[ForceFed70]

Put up a vapor barrier. This is exactly why a vapor barrier is used.

 

[mwe3302]

All 3 lumber co. Also said "DO NOT " put up plastic aka a vapor barrer as the kraft face insulation is the vapor barrier. If it was unfaced insulation then i would have. I used dura vent baffles to direct air flow to go to the ridge vent. I am currently puuting up 1/2 inch sheet rock and as soon as that is done i will be mudding sanding and painting it. I hope this stops it, i think that it was coming from that standing water from under my ATV.

 

[nwav8tor]

Not an expert here, but who cares if the moisture is from the concrete or your wet equipment - either way your goal is to keep it out of the insulation and the attis space! If the kraft acts as your vapor barrier, what harm would it do to add plastic right below it? I'd be worried that the kraft would have too many avenues of penetration for moisture, especially along the joists. Even if you don't add the plastic, use a good vapor barrier primer on the sheetrock before you paint.

My .02
Paul

 

[motorcycle79]

Do not add plastic you will have a bigger problem trapping moisture In between. My guess is the moisture is coming from your wheeler. Try to brush it off before u bring it in and squeegee out the puddles and get a dehumidifier. Get a humidity gauge and see what happens when u pull in your wheeler
Marty

 

[mwe3302]

Thank-you paul and marty for your input. I definitly will try the vapor barrier primer after mudding and will try to brush off ATV better , might have to break out the portable air compressor to get all the snow out of all the nooks and crannys on the Grizzly.

Marty , i will try a humidity gauge also. I can't wait to get the floor sealed and painted. How long should i wait to do the floor? Where its a slab that has only been there for 10 months, should i wait another year to let it cure some more, and how will sealing the floor affect the moisture inside the cenment , or am i just worrying to much? Thanks in advance, mike.

 

[Andamo]

Put some sort of ceiling fan in there also and that'll help dry up the water.

 

[mwe3302]

Put some sort of ceiling fan in there also and that'll help dry up the water.

Andamo : i only have 8 foot ceilings so i can't really afford to loose any ceiling space, i am going to be installing a HotDawg ceiling heater later this year. It looks similar to the BigMax. I used a larger tarp under my ATV all winter in hopes of the water staying on the tarp versus the floor but it still found its way through it

 

[motorcycle79]

That hot dawg will work good to burn up some of that humidity. I would think your good to seal concrete after 10 months but I am no concrete expert. I have seen people seal within a week of pouring concrete
Marty

 

[Andamo]

That's all the height I have in my garage and I found a 32'' ceiling hugger fan which works great. You don't need a huge fan either, just something to keep the air moving. I have the same problem with bringing in our cars that have snow on and under them and naturally the snowblower. I have a Reznor heater and along with the ceiling fan, I've never had a moisture problem.

 

[buddyboy]

yes do NOT add another vapor barrier. moisture will just get trapped inside.

water likes to condense on cold surfaces.

I say it wouldn't hurt to tape the seams on the kraft paper, that way you can make sure you have 100% seal.

you are sealing OUT cold air flow and sealing IN warm moist air.

right now that moist air is hitting cold craft paper and you're getting condensation.

you also only have R19, consider adding more to get to a total of R40 or even R50+ to keep the cold air away from your interior surfaces.

also I doubt that water is coming up thru your slab (unless you have a high water table), more than likely your slab is just colder than the air, and water is condensing on it.

the reason foam insulation stops water from forming on the slab is because an insulated slab can stay closer to air temps.

fans move air around and keep surface temps more uniform and you're less likely to have cold spots for water vapor to condense.

think of a cold bottle of beer in the summer time, water collects on the outside of the bottle. beer isn't leaking thru tiny holes it's water vapor in the air condensing on a colder surface.

heating the air inside the garage will also warm all your surfaces making condensation a non issue... unless that warm air gets into an unvented attic space.

good luck

 

[mwe3302]

yes do NOT add another vapor barrier. moisture will just get trapped inside.

water likes to condense on cold surfaces.

I say it wouldn't hurt to tape the seams on the kraft paper, that way you can make sure you have 100% seal.

you are sealing OUT cold air flow and sealing IN warm moist air.

right now that moist air is hitting cold craft paper and you're getting condensation.

you also only have R19, consider adding more to get to a total of R40 or even R50+ to keep the cold air away from your interior surfaces.

also I doubt that water is coming up thru your slab (unless you have a high water table), more than likely your slab is just colder than the air, and water is condensing on it.

the reason foam insulation stops water from forming on the slab is because an insulated slab can stay closer to air temps.

fans move air around and keep surface temps more uniform and you're less likely to have cold spots for water vapor to condense.

think of a cold bottle of beer in the summer time, water collects on the outside of the bottle. beer isn't leaking thru tiny holes it's water vapor in the air condensing on a colder surface.

heating the air inside the garage will also warm all your surfaces making condensation a non issue... unless that warm air gets into an unvented attic space.

good luck

Buddyboy, thanks so much for your knowledge, i just finished sheetrocking the ceiling today, so tapeing the kraft insulation seams will not be possible now. I am going to let my back rest for a few days and then tape and mud all the seams.
After its sanded and i do another coat, i will try some of that vaper sealing primer. Can someone recomend a vapor sealing primer. I want to get the right stuff.

 

[mwe3302]

That hot dawg will work good to burn up some of that humidity. I would think your good to seal concrete after 10 months but I am no concrete expert. I have seen people seal within a week of pouring concrete
Marty

That's all the height I have in my garage and I found a 32'' ceiling hugger fan which works great. You don't need a huge fan either, just something to keep the air moving. I have the same problem with bringing in our cars that have snow on and under them and naturally the snowblower. I have a Reznor heater and along with the ceiling fan, I've never had a moisture problem.

Marty: Well thats good to know about the Hot Dawg , i am going to wait untill this summer when the rainy season is gone, like around july or august to seal it.

Andamo: i will look around for one of those fans, where did you buy yours at?

Thank you both......Mike.

 

[Highbeam]

Have you gone into the attic, lifted a section of insulation to see if it is still wet? The curiosity must be killing you.

I have no intention of ever using batt insulation in any ceiling. Unless you have no other choice it is always better to blow in FG or cellulose. The VB can be painted on or you can use plastic before the sheetrock.

I am curious about why you were getting condensation on the vapor barrier. Normally, the inside of the insulation is the warm side and is too warm for condensation. It must be really really cold in your area or you have water coming in from above.

 

[mwe3302]

Have you gone into the attic, lifted a section of insulation to see if it is still wet? The curiosity must be killing you.

I have no intention of ever using batt insulation in any ceiling. Unless you have no other choice it is always better to blow in FG or cellulose. The VB can be painted on or you can use plastic before the sheetrock.

I am curious about why you were getting condensation on the vapor barrier. Normally, the inside of the insulation is the warm side and is too warm for condensation. It must be really really cold in your area or you have water coming in from above.

Already felt down through the insulation the very day noticed it, attic area is completely dry, i have never had an issue with batt insulation ever. Condensation was on kraft paper side only.

I am guessing that it was coming from the puddle under the ATV, It has not done it since.
as far as being cold in my area, this has been a very odd winter, the day i found the condensation, it was 86 degrees that day, and it was 82 the day befor. Thats really unheard of for northern Maine.

And i am really curiuos as to why there was condensation on just the kraft side as well......mike.

 

[Highbeam]

Water condenses on cold things, think coke can. So the kraft paper was colder than the moisture laden air. The moisture laden air being on the living side makes sense and is a good thing, it tells you that the kraft paper prevented the moisture laden air from infiltrating.

Unless you have a leak from above, everything looks good.

 

[mwe3302]

Well that is good to know highbeam, hopefully it keeps the moisture laden air off the other things. Thank you for your knowledge on this.

 

[cpelletier7]

Did you end up solving this issue? I'm having the same problem in my garage and it seems like the wet paper is starting to get mold on it and possibly on my rafters where it's stapled.

 

[Jeepster04]

Theres two ways to keep this from happening..

#1: Remove the moisture from the air. Either with a dehumidifier or stop the moisture from coming into the building in the first place.

#2: Everything in the building needs to be above the dew point so the moisture doesnt form on the surfaces.

Its that simple. And I imagine the OP is long gone.

 

[cpelletier7]

So basically seal my concrete floor and upgrade the 70yr old windows? I'm guessing I have to scrap the insulation though due to it already starting mold growth

 

[Falcon67]

Note - OPs last activity on GJ was over 2 years ago.

 

[6768rogues]

I would put up a ceiling fan and run it on low all the time. If that does not do it, slash the Kraft vapor barrier with a knife and put plastic over it.

 

[Marctrees]

6768 - Please explain why you would slash the paper, and then, after that, apply poly??

Trying to understand the logic there. Marc

 

[yeldogt]

6768 - Please explain why you would slash the paper, and then, after that, apply poly??

Trying to understand the logic there. Marc

It's very old thread -- But, the theory with the plastic. You cut the paper VB -- by cutting the paper it is no longer a vapor barrier -- cover with plastic .. plastic now VB.

People started to use plastic for two reason -- if you seal the seams it will act as a air infiltration barrier .. it's also a complete VB. The first (air barrier) is great the second is the problem.

Plastic is not recommended as a VB any more -- it causes all kinds of problems. I guess in a completely dry environment with a lot of wind it would work.

In the OP case the water is just going to sit on the plastic -- and if you drywall ........moisture will migrate through the drywall and sit on the plastic.